An algorithm was proposed to simulate the withering deformation of plant leaves by wrinkle and curl due to dehydration, based on cell dynamics and time-varying external force. First, a leaf boundary expansion algorithm was proposed to locate the feature points on the tip of the vein and construct the primary vein using a discrete geodesic path. Second, a novel mass-spring system by cell dynamics and a non-uniform mass distribution was defined to accelerate the movement of the boundary cells. Third, the cell swelling force was defined and adjusted to generate wrinkle deformation along with dehydration. Fourth, the time-varying external force on the feature points was defined to generate the curl deformation by adjusting the initial value of the external force and multiple iterative parameters. The implicit midpoint method was used to solve the equation of motion. The experimental results showed that our algorithm could simulate the wrinkle and curl deformation caused by dehydration and withering of leaves with high authenticity.